I wouldn't plan a 4.5 stroke in a 440 block for anything beyond about 600 hp, and then only if I had a very light rotating assembly and / or a center weighted crank to help relieve stress on the bottom end combined with small port heads. I ran a 4.5 x 4.350 bore combo for a while, shifting at 5700 till I ran over the crank. It was cracked and only went about 300 passes. The block showed cap walk though.